前言

Swift版本的h264编码很少，我也是参照简书大佬的文章搞的，可以正常跑，放心cv。
不了解ReplayKit2和app extension的自行百度。

demo实现

拉起app extension

let picker = RPSystemBroadcastPickerView.init(frame: CGRectMake(0, 0, 1, 1))
picker.preferredExtension = "你的app extention bundle id"
 picker.showsMicrophoneButton = true
        
 for subView in picker.subviews {
        if let btn = subView as? UIButton {
             btn.sendActions(for: .allTouchEvents)
        }
 }

上面代码会弹起一个广播列表，选择你的extension，点击开始直播按钮，会进入你的app extension，开始录屏。

共享代码文件

app extension可以使用宿主代码，只需要按照下图配置即可：

Xnip2024-01-29_21-26-41.jpg

app extension使用宿主工程pod库

在宿主podfile app extension target下编写添加三方库就行，如下图：

Xnip2024-01-29_21-31-00.jpg

RPBroadcastSampleHandler

class SampleHandler: RPBroadcastSampleHandler {
    private var socketMananger: SocketManager?
    private var encoder: LYH264Encoder?
    
    override func broadcastStarted(withSetupInfo setupInfo: [String : NSObject]?) {
        // User has requested to start the broadcast. Setup info from the UI extension can be supplied but optional.
        setup()
    }
    
    override func broadcastPaused() {
        // User has requested to pause the broadcast. Samples will stop being delivered.
    }
    
    override func broadcastResumed() {
        // User has requested to resume the broadcast. Samples delivery will resume.
    }
    
    override func broadcastFinished() {
        // User has requested to finish the broadcast.
        socketMananger?.dispose()
        encoder?.dispose()
    }
    
    override func processSampleBuffer(_ sampleBuffer: CMSampleBuffer, with sampleBufferType: RPSampleBufferType) {
        switch sampleBufferType {
        case RPSampleBufferType.video:
            // Handle video sample buffer
            encode(sampleBuffer)
            break
        case RPSampleBufferType.audioApp:
            // Handle audio sample buffer for app audio
            break
        case RPSampleBufferType.audioMic:
            // Handle audio sample buffer for mic audio
            break
        @unknown default:
            // Handle other sample buffer types
            fatalError("Unknown type of sample buffer")
        }
    }
    
    func setup() {
        socketMananger = SocketManager(isServer: true)
        let scale = UIScreen.main.scale
        encoder = LYH264Encoder(width: Int32(UIScreen.main.bounds.width * scale), height: Int32(UIScreen.main.bounds.height * scale), bitRate: nil, fps: 30)
    }
    
    func encode(_ sampleBuffer: CMSampleBuffer) {
        encoder?.encodeVideo(sampleBuffer: sampleBuffer)
        encoder?.videoEncodeCallback = { [weak self] (data) in
            self?.socketMananger?.sendParam([KSocketDataType : LYSocketDataType.sampleBuffer.rawValue, KSocketDataKey: data])
        }
    }
    
    func senData(_ sampleBuffer: CMSampleBuffer) {
        if let string = self.sampleBufferToBase64(sampleBuffer: sampleBuffer) {
            self.socketMananger?.sendParam([KSocketDataType : LYSocketDataType.image.rawValue, KSocketDataKey: string])
        }
    }
}

h264编码

原理就不说了，代码也大同小异，以下代码Swift 5.x跑没毛病

import VideoToolbox

class LYH264Encoder {
    public var videoEncodeCallback: ((Data) -> Void)?
    public var width: Int32 = 375
    public var height: Int32 = 852
    
    private var bitRate : Int32 = 375 * 852 * 3 * 4
    private var fps: Int32 = 10
    private var frameID: Int64 = 0
    
    private var encodeCallBack: VTCompressionOutputCallback?
    private var encodeQueue = DispatchQueue(label: "com.ly_encode")
    private var callBackQueue = DispatchQueue(label: "com.ly_encode_callBack")
    private var encodeSession: VTCompressionSession?
    
    public init(width: Int32 = 375, height: Int32 = 852, bitRate: Int32?, fps: Int32?) {
        self.width = width
        self.height = height
        self.bitRate = bitRate != nil ? bitRate! : width * height * 3 * 4
        self.fps = fps != nil ? fps! : 10
        
        setupCallBack()
        initVideoToolBox()
    }
    
    public func encodeVideo(sampleBuffer: CMSampleBuffer) {
        if self.encodeSession == nil {
            initVideoToolBox()
        }
        
        encodeQueue.async {
            guard let encodeSession = self.encodeSession else {
                return
            }
            
            guard let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {
                return
            }
            
            var time = CMTime(value: self.frameID, timescale: 1000)
            self.frameID += 1
            
            if #available(iOS 15, *) {  // iOS 15 timescale = 1000， 码率很低，马赛克
                time = CMTime(value: self.frameID, timescale: 100)
            }
            
            var flags: VTEncodeInfoFlags = []
            //编码
            let state = VTCompressionSessionEncodeFrame(encodeSession, imageBuffer: imageBuffer, presentationTimeStamp: time, duration: .invalid, frameProperties: nil, sourceFrameRefcon: nil, infoFlagsOut: &flags)
            if state != 0 {
                print("VTCompression: encode failed: status \(state)")
            }
        }
    }
    
    func dispose() {
        frameID = 0
        if let session = encodeSession {
            VTCompressionSessionCompleteFrames(session, untilPresentationTimeStamp: .invalid)
            VTCompressionSessionInvalidate(session);
            encodeSession = nil;
        }
    }
    
    deinit {
        dispose()
    }
    
    private func initVideoToolBox() {
        // session
        let status = VTCompressionSessionCreate(allocator: kCFAllocatorDefault,  // 会话的分配器
                                                width: width,   // 帧的宽度
                                                height: height,  // 帧的高度
                                                codecType: kCMVideoCodecType_H264, // 编解码器的类型,表示使用h.264进行编码
                                                encoderSpecification: nil,  // 指定必须使用的特定视频编码
                                                imageBufferAttributes: nil,  // 源像素缓冲区所需的属性，用于创建像素缓冲池
                                                compressedDataAllocator: nil, // 压缩数据的分配器
                                                outputCallback: encodeCallBack, //encodeCallBack, // 当一次编码结束会在该函数进行回调,可以在该函数中将数据,写入文件中
                                                refcon:  unsafeBitCast(self, to: UnsafeMutableRawPointer.self),
                                                compressionSessionOut: &self.encodeSession
        )
        
        if status != 0 {
            print("创建编码会话失败")
            return
        }
        
        guard let encodeSession = encodeSession else {
            return
        }
        
        //设置实时编码输出
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_RealTime, value: kCFBooleanTrue)
        //设置编码方式
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_ProfileLevel, value: kVTProfileLevel_H264_Baseline_AutoLevel)
        //设置是否产生B帧(因为B帧在解码时并不是必要的,是可以抛弃B帧的)
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_AllowFrameReordering, value: kCFBooleanFalse)
        //设置关键帧间隔
        var frameInterval = 10
        let number = CFNumberCreate(kCFAllocatorDefault, CFNumberType.intType, &frameInterval)
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_MaxKeyFrameInterval, value: number)
        
        //设置期望帧率，不是实际帧率
        let fpscf = CFNumberCreate(kCFAllocatorDefault, CFNumberType.intType, &fps)
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_ExpectedFrameRate, value: fpscf)
        
        //设置码率平均值，单位是bps。码率大了话就会非常清晰，但同时文件也会比较大。码率小的话，画面会模糊
        let bitrateAverage = CFNumberCreate(kCFAllocatorDefault, CFNumberType.intType, &bitRate)
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_AverageBitRate, value: bitrateAverage)
        
        //码率限制
        let bitRatesLimit: CFArray = [bitRate * 5 / 8, 1] as CFArray
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_DataRateLimits, value: bitRatesLimit)
        
        /// 压缩质量
        var quality = 1
        VTSessionSetProperty(encodeSession, key: kVTCompressionPropertyKey_Quality, value: CFNumberCreate(kCFAllocatorDefault, CFNumberType.floatType, &quality))
    }
    
    private func gotSpsPps(sps: Data, pps: Data) {
        // startcode sps pps i b p startcode .....
        let startCode = Data([0x00, 0x00, 0x00, 0x01])
        var h264Data = Data()
        h264Data.append(startCode)
        h264Data.append(sps)
        callBackQueue.async {
            self.videoEncodeCallback?(h264Data)
        }
        
        var ppsData = Data()
        ppsData.append(startCode)
        ppsData.append(pps)
        callBackQueue.async {
            self.videoEncodeCallback?(ppsData)
        }
    }

    private func gotEncodedData(_ data: Data, isKeyFrame: Bool) {
        let startCode = Data([0x00, 0x00, 0x00, 0x01])
        var h264Data = Data()
        h264Data.append(startCode)
        h264Data.append(data)
        callBackQueue.async {
            self.videoEncodeCallback?(h264Data)
        }
    }
    
    private func setupCallBack() {
        //编码完成回调
        encodeCallBack = { (outputCallbackRefCon, sourceFrameRefCon, status, infoFlags, sampleBuffer)  in
            // 1.判断状态是否等于没有错误
            if status != noErr {
                print("encode with err")
                return
            }
            
            guard let sampleBuffer = sampleBuffer else {
                print("no buffer")
                return
            }
            
            guard CMSampleBufferDataIsReady(sampleBuffer) else {
                print("didCompressH264 data is not ready ")
                return
            }
            
            // 2.根据传入的参数获取对象
            let encoder: LYH264Encoder = unsafeBitCast(outputCallbackRefCon, to: LYH264Encoder.self)
            
            // 3.判断是否是关键帧
            let attachmentsArray = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, createIfNecessary: true)
            let attachments = unsafeBitCast(CFArrayGetValueAtIndex(attachmentsArray, 0), to: CFDictionary.self)
            let isKeyframe = !CFDictionaryContainsKey(attachments, Unmanaged.passUnretained(kCMSampleAttachmentKey_NotSync).toOpaque())

            // 判断当前帧是否为关键帧
            // 获取sps & pps数据
            if isKeyframe {
                print("获取到关键帧")
                // 获取编码后的信息（存储于CMFormatDescriptionRef中）
                let format = CMSampleBufferGetFormatDescription(sampleBuffer)
                
                // 获取SPS信息
                var sparameterSetSize: Int = 0
                var sparameterSetCount: Int = 0
                var sparameterSet: UnsafePointer<UInt8>?
                CMVideoFormatDescriptionGetH264ParameterSetAtIndex(format!, parameterSetIndex: 0, parameterSetPointerOut: &sparameterSet, parameterSetSizeOut: &sparameterSetSize, parameterSetCountOut: &sparameterSetCount, nalUnitHeaderLengthOut: nil)
                
                // 获取PPS信息
                var pparameterSetSize: Int = 0
                var pparameterSetCount: Int = 0
                var pparameterSet: UnsafePointer<UInt8>?
                CMVideoFormatDescriptionGetH264ParameterSetAtIndex(format!, parameterSetIndex: 1, parameterSetPointerOut: &pparameterSet, parameterSetSizeOut: &pparameterSetSize, parameterSetCountOut: &pparameterSetCount, nalUnitHeaderLengthOut: nil)
                
                // 装sps/pps转成NSData
                let sps = Data(bytes: sparameterSet!, count: sparameterSetSize)
                let pps = Data(bytes: pparameterSet!, count: pparameterSetSize)
                
                // 写入文件
                encoder.gotSpsPps(sps: sps, pps: pps)
            }
            
            // 获取数据块
            guard let dataBuffer = CMSampleBufferGetDataBuffer(sampleBuffer) else {
                return
            }
            
            var length: size_t = 0
            var totalLength: size_t = 0
            var dataPointer: UnsafeMutablePointer<Int8>?
            
            let statusCodeRet = CMBlockBufferGetDataPointer(dataBuffer, atOffset: 0, lengthAtOffsetOut: &length, totalLengthOut: &totalLength, dataPointerOut: &dataPointer)
            
            if statusCodeRet == noErr {
                var bufferOffset: size_t = 0
                let AVCCHeaderLength: Int = 4 // 返回的nalu数据前四个字节不是0001的startcode，而是大端模式的帧长度length
                
                // 循环获取nalu数据
                while bufferOffset < totalLength - AVCCHeaderLength {
                    var NALUnitLength: UInt32 = 0
                    // Read the NAL unit length
                    memcpy(&NALUnitLength, dataPointer! + bufferOffset, AVCCHeaderLength)
                    
                    // 从大端转系统端
                    NALUnitLength = CFSwapInt32BigToHost(NALUnitLength)
                    
                    let data = Data(bytes: dataPointer! + bufferOffset + AVCCHeaderLength, count: Int(NALUnitLength))
                    encoder.gotEncodedData(data, isKeyFrame: isKeyframe)
                    
                    // 移动到写一个块，转成NALU单元
                    // Move to the next NAL unit in the block buffer
                    bufferOffset += AVCCHeaderLength + Int(NALUnitLength)
                }
            }
        }
    }
}

h264解码

enum LYH264DecodeType {
    /// CVPixcelBuffer 图片
    case imageBuffer
    /// h264 编码结构
    case sampleBuffer
}

class LYH264Decoder {
    /// 解码类型
    public var returnType: LYH264DecodeType = .sampleBuffer
    /// 解码后image结果回调
    public var videoDecodeCallback: ((CVImageBuffer?) -> Void)?
    /// 解码后sample结果回调
    public var videoDecodeSampleBufferCallback: ((CMSampleBuffer?) -> Void)?
    
    private var width: Int32 = 375
    private var height: Int32 = 852
    
    private var spsData: Data?
    private var ppsData: Data?
    private var decompressionSession: VTDecompressionSession?
    private var decodeDesc: CMVideoFormatDescription?
    private var callback: VTDecompressionOutputCallback?
    private var decodeQueue = DispatchQueue(label: "com.ly_decode")
    private var callBackQueue = DispatchQueue(label: "com.ly_decode_callBack")

    public init(width: Int32, height: Int32) {
        self.width = width
        self.height = height
    }
    
    public func decode(data: Data) {
        decodeQueue.async {
            let length: UInt32 =  UInt32(data.count)
            self.decodeByte(data: data, size: length)
        }
    }
    
    
    private func decodeByte(data: Data, size: UInt32) {
        //数据类型:frame的前4个字节是NALU数据的开始码，也就是00 00 00 01，
        // 将NALU的开始码转为4字节大端NALU的长度信息
        let naluSize = size - 4
        let length: [UInt8] = [
            UInt8(truncatingIfNeeded: naluSize >> 24),
            UInt8(truncatingIfNeeded: naluSize >> 16),
            UInt8(truncatingIfNeeded: naluSize >> 8),
            UInt8(truncatingIfNeeded: naluSize)
        ]
        
        var frameByte: [UInt8] = length
        [UInt8](data).suffix(from: 4).forEach { (item) in
            frameByte.append(item)
        }
        
        let bytes = frameByte //[UInt8](frameData)
        // 第5个字节是表示数据类型，转为10进制后，7是sps, 8是pps, 5是IDR（I帧）信息
        let type: Int  = Int(bytes[4] & 0x1f)
        switch type {
            case 0x05:
                print("-收到关键帧，准备编码-")
                if initDecoder() {
                    print("!收到关键帧，开始编码!")
                    decode(frame: bytes, size: size)
                }
                
            case 0x06:
    //            print("增强信息")
                break
            case 0x07:
                print("- sps -")
                spsData = data
            case 0x08:
                print("- pps -")
                ppsData = data
            default:
                if initDecoder() {
                    decode(frame: bytes, size: size)
                }
        }
    }
    
    private func decode(frame: [UInt8], size: UInt32) {
        var blockBUffer: CMBlockBuffer?
        var frame1 = frame
        //创建blockBuffer
        /*!
         参数1: structureAllocator kCFAllocatorDefault
         参数2: memoryBlock  frame
         参数3: frame size
         参数4: blockAllocator: Pass NULL
         参数5: customBlockSource Pass NULL
         参数6: offsetToData  数据偏移
         参数7: dataLength 数据长度
         参数8: flags 功能和控制标志
         参数9: newBBufOut blockBuffer地址,不能为空
         */
        let blockState = CMBlockBufferCreateWithMemoryBlock(allocator: kCFAllocatorDefault,
                                           memoryBlock: &frame1,
                                           blockLength: Int(size),
                                           blockAllocator: kCFAllocatorNull,
                                           customBlockSource: nil,
                                           offsetToData:0,
                                           dataLength: Int(size),
                                           flags: 0,
                                           blockBufferOut: &blockBUffer)
        if blockState != 0 {
            print("创建blockBuffer失败")
        }

        var sampleSizeArray: [Int] = [Int(size)]
        var sampleBuffer: CMSampleBuffer?
        //创建sampleBuffer
        /*
         参数1: allocator 分配器,使用默认内存分配, kCFAllocatorDefault
         参数2: blockBuffer.需要编码的数据blockBuffer.不能为NULL
         参数3: formatDescription,视频输出格式
         参数4: numSamples.CMSampleBuffer 个数.
         参数5: numSampleTimingEntries 必须为0,1,numSamples
         参数6: sampleTimingArray.  数组.为空
         参数7: numSampleSizeEntries 默认为1
         参数8: sampleSizeArray
         参数9: sampleBuffer对象
         */
        let readyState = CMSampleBufferCreateReady(allocator: kCFAllocatorDefault,
                                  dataBuffer: blockBUffer,
                                  formatDescription: decodeDesc,
                                  sampleCount: CMItemCount(1),
                                  sampleTimingEntryCount: CMItemCount(),
                                  sampleTimingArray: nil,
                                  sampleSizeEntryCount: CMItemCount(1),
                                  sampleSizeArray: &sampleSizeArray,
                                  sampleBufferOut: &sampleBuffer)
        
        guard let buffer = sampleBuffer, readyState == kCMBlockBufferNoErr else {
            print("解码失败")
            return
        }
        
        if returnType == .sampleBuffer {
            if let attachmentArray = CMSampleBufferGetSampleAttachmentsArray(buffer, createIfNecessary: true) {
                let dic = unsafeBitCast(CFArrayGetValueAtIndex(attachmentArray, 0), to: CFMutableDictionary.self)
                CFDictionarySetValue(dic,
                                     Unmanaged.passUnretained(kCMSampleAttachmentKey_DisplayImmediately).toOpaque(),
                                     Unmanaged.passUnretained(kCFBooleanTrue).toOpaque())
            }
            videoDecodeSampleBufferCallback?(sampleBuffer)
            return
        }
    
        //解码数据为CVPixcelBuffer
        /*
         参数1: 解码session
         参数2: 源数据 包含一个或多个视频帧的CMsampleBuffer
         参数3: 解码标志
         参数4: 解码后数据outputPixelBuffer
         参数5: 同步/异步解码标识
         */
        let sourceFrame: UnsafeMutableRawPointer? = nil
        var inforFalg = VTDecodeInfoFlags.asynchronous
        let decodeState = VTDecompressionSessionDecodeFrame(self.decompressionSession!,
                                                            sampleBuffer: sampleBuffer!,
                                                            flags: VTDecodeFrameFlags._EnableAsynchronousDecompression,
                                                            frameRefcon: sourceFrame,
                                                            infoFlagsOut: &inforFalg
        )
        
        if decodeState != 0 {
            print("解码失败")
        }
    }
    
    private func initDecoder() -> Bool {
        if decompressionSession != nil {
            return true
        }
        
        guard spsData != nil, ppsData != nil else {
            return false
        }

        //处理sps/pps
        var sps: [UInt8] = []
        [UInt8](spsData!).suffix(from: 4).forEach { (value) in
            sps.append(value)
        }
        
        var pps: [UInt8] = []
        [UInt8](ppsData!).suffix(from: 4).forEach{(value) in
            pps.append(value)
        }
        
        let spsAndpps = [sps.withUnsafeBufferPointer{$0}.baseAddress!,pps.withUnsafeBufferPointer{$0}.baseAddress!]
        let sizes = [sps.count,pps.count]

        /**
        根据sps pps设置解码参数
        param kCFAllocatorDefault 分配器
        param 2 参数个数
        param parameterSetPointers 参数集指针
        param parameterSetSizes 参数集大小
        param naluHeaderLen nalu nalu start code 的长度 4
        param _decodeDesc 解码器描述
        return 状态
        */
        let descriptionState = CMVideoFormatDescriptionCreateFromH264ParameterSets(allocator: kCFAllocatorDefault,
                                                                                   parameterSetCount: 2,
                                                                                   parameterSetPointers: spsAndpps,
                                                                                   parameterSetSizes: sizes,
                                                                                   nalUnitHeaderLength: 4,
                                                                                   formatDescriptionOut: &decodeDesc
        )
        
        if descriptionState != 0 {
            print("description创建失败" )
            return false
        }
        
        //解码回调设置
        /*
         VTDecompressionOutputCallbackRecord 是一个简单的结构体，它带有一个指针 (decompressionOutputCallback)，指向帧解压完成后的回调方法。你需要提供可以找到这个回调方法的实例 (decompressionOutputRefCon)
         */
        setupCallBack()
        var callbackRecord = VTDecompressionOutputCallbackRecord(decompressionOutputCallback: callback, decompressionOutputRefCon: unsafeBitCast(self, to: UnsafeMutableRawPointer.self))
        
        /*
         解码参数:
        * kCVPixelBufferPixelFormatTypeKey:摄像头的输出数据格式
         kCVPixelBufferPixelFormatTypeKey，已测可用值为
            kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange，即420v
            kCVPixelFormatType_420YpCbCr8BiPlanarFullRange，即420f
            kCVPixelFormatType_32BGRA，iOS在内部进行YUV至BGRA格式转换
         YUV420一般用于标清视频，YUV422用于高清视频，这里的限制让人感到意外。但是，在相同条件下，YUV420计算耗时和传输压力比YUV422都小。
         
        * kCVPixelBufferWidthKey/kCVPixelBufferHeightKey: 视频源的分辨率 width*height
         * kCVPixelBufferOpenGLCompatibilityKey : 它允许在 OpenGL 的上下文中直接绘制解码后的图像，而不是从总线和 CPU 之间复制数据。这有时候被称为零拷贝通道，因为在绘制过程中没有解码的图像被拷贝.
         
         */
        let imageBufferAttributes = [
            kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_420YpCbCr8BiPlanarFullRange,
            kCVPixelBufferWidthKey: width,
            kCVPixelBufferHeightKey: height,
//            kCVPixelBufferOpenGLCompatibilityKey:true
            ] as [CFString : Any]
        
        //创建session
        
        /*!
         @function    VTDecompressionSessionCreate
         @abstract    创建用于解压缩视频帧的会话。
         @discussion  解压后的帧将通过调用OutputCallback发出
         @param    allocator  内存的会话。通过使用默认的kCFAllocatorDefault的分配器。
         @param    videoFormatDescription 描述源视频帧
         @param    videoDecoderSpecification 指定必须使用的特定视频解码器.NULL
         @param    destinationImageBufferAttributes 描述源像素缓冲区的要求 NULL
         @param    outputCallback 使用已解压缩的帧调用的回调
         @param    decompressionSessionOut 指向一个变量以接收新的解压会话
         */
        let state = VTDecompressionSessionCreate(allocator: kCFAllocatorDefault,
                                                 formatDescription: decodeDesc!,
                                                 decoderSpecification: nil,
                                                 imageBufferAttributes: imageBufferAttributes as CFDictionary,
                                                 outputCallback: &callbackRecord,
                                                 decompressionSessionOut: &decompressionSession
        )
        
        if state != 0 {
            print("创建decodeSession失败")
        }
        
        VTSessionSetProperty(self.decompressionSession!, key: kVTDecompressionPropertyKey_RealTime, value: kCFBooleanTrue)
        return true
    }

    //解码成功的回掉
    private func setupCallBack() {
        /*
         VTDecompressionOutputCallback 回调方法包括七个参数：
                参数1: 回调的引用
                参数2: 帧的引用
                参数3: 一个状态标识 (包含未定义的代码)
                参数4: 指示同步/异步解码，或者解码器是否打算丢帧的标识
                参数5: 实际图像的缓冲
                参数6: 出现的时间戳
                参数7: 出现的持续时间
         */
        //(UnsafeMutableRawPointer?, UnsafeMutableRawPointer?, OSStatus, VTDecodeInfoFlags, CVImageBuffer?, CMTime, CMTime) -> Void
        callback = { decompressionOutputRefCon, sourceFrameRefCon, status,inforFlags, imageBuffer, presentationTimeStamp, presentationDuration in
            let decoder: LYH264Decoder = unsafeBitCast(decompressionOutputRefCon, to: LYH264Decoder.self)
            
            guard imageBuffer != nil else {
                return
            }
            
            if let block = decoder.videoDecodeCallback  {
                decoder.callBackQueue.async {
                    block(imageBuffer)
                }
            }
        }
    }
    
    deinit {
        if decompressionSession != nil {
            VTDecompressionSessionInvalidate(decompressionSession!)
            decompressionSession = nil
        }
        
    }
}

socket

解决粘包就好，我上一篇文章也提到过，有兴趣可以去看看。

import CocoaAsyncSocket
import SVProgressHUD
import Foundation

fileprivate let ipStr = "172.20.10.1"
fileprivate let myPort: UInt16 = 12345  
/// 字典key "type"
let KSocketDataType = "type"
/// 字典key "data"
let KSocketDataKey = "data"
fileprivate let bodyLegth = 4 //信息长度位

enum LYSocketDataType: String, CaseIterable {
    /// ping
    case ping
    /// 图片
    case image
    ///  录屏视频图片数据容器
    case sampleBuffer
    /// 字符串消息
    case string
    /// 单击
    case touch
    /// 双击
    case dobleTap
    /// 滑动
    case slide
}

protocol SocketManagerDelegate: AnyObject {
    func receivedImage(_ image: UIImage)
    func receivedPoint(_ x: Double, _ y: Double)
    func receivedKeyWord(_ keyWord: String)
    func receivedSampleBuffer(_ sampleBuffer: Data)
}

class SocketManager: NSObject {
    // MARK: - property
    private var socket: GCDAsyncSocket!
    //作为服务端时，连接的客户端
    private var clientSocket: GCDAsyncSocket?
    /// 是否为服务端
    public var isServer: Bool

    /// 代理
    public weak var delegate: SocketManagerDelegate?
    /// 是否已连接客户端
    private(set) var isConnectClient = false

    // 接收缓存，用于解决粘包
    private lazy var dataBuffer: Data = {
        let data = Data()
        return data
    }()

    // 定时器，发心跳包
    private lazy var timer: Timer = {
        let timer = Timer(timeInterval: 30, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
        RunLoop.current.add(timer, forMode: .common)
        return timer
    }()
    
    //MARK: - cycle
    init(isServer: Bool) {
        self.isServer = isServer
        super.init()
        
        let queue = DispatchQueue(label: "com.lanyou.socket")
        socket = GCDAsyncSocket(delegate: self, delegateQueue: queue)

        if isServer {
            setupServer()
        } else {
            setupClient()
        }
    }
    
    fileprivate func setupServer() {
        do {
            try socket.accept(onPort: myPort)
        } catch {
            print("socket服务器启动失败: \(error.localizedDescription)")
        }
    }

    fileprivate func setupClient() {
        do {
            try socket.connect(toHost: ipStr, onPort: myPort)
        } catch {
            print("socket连接服务器失败: \(error.localizedDescription)")
        }
    }
    
    deinit {
        dispose()
    }
    
    public func dispose() {
        socket.disconnect()
        clientSocket?.disconnect()
        if !isServer {
            timer.invalidate()
        }
    }
    
    // MARK: - sendData
    public func sendParam(_ param: [String : Any]) {
        if isServer && !isConnectClient {
            return
        }
                    
        var dict = param as [String : Any]
        // 处理value为data的情况
        for (key, value) in dict {
            if let dataValue = value as? Data {
                if let base64String = dataToBase64String(dataValue) {
                    dict[key] = base64String
                }
            }
        }
    
        // dict - > data
        do {
            let jsonData = try JSONSerialization.data(withJSONObject: dict, options: [])
            let jsonString = String(data: jsonData, encoding: .utf8)
            guard let json = jsonString else { return }
            if let data = json.data(using: .utf8) {
                sendData(data)
            }
        } catch {
            print("字典转data出错: \(error)")
        }
    }
    
    fileprivate func dataToBase64String(_ data: Data) -> String? {
        return data.base64EncodedString()
    }
        
    // 粘包封包
    fileprivate func sendData(_ data: Data) {
        // 拼接数据 -> 带有长度信息的数据包
        var messageLength: UInt32 = UInt32(data.count)
        let lengthData = Data(bytes: &messageLength, count: MemoryLayout<UInt32>.size) //4字节
        var sendData = lengthData
        sendData.append(data)
        
        if isServer {
            clientSocket?.write(sendData, withTimeout: -1, tag: 0)
        } else {
            socket.write(sendData, withTimeout: -1, tag: 0)
        }
    }
    
    fileprivate func jsonToDictionary(_ jsonString: String) -> [String : Any]? {
        if let jsonData = jsonString.data(using: .utf8) {
            do {
                if let jsonDictionary = try JSONSerialization.jsonObject(with: jsonData, options: []) as? [String: Any] {
                    return jsonDictionary
                } else {
                    print("json字符串转字典失败")
                }
            } catch {
                print("json转字典err: \(error.localizedDescription)")
            }
        }
        return nil
    }
    
    // MARK: - Timer
    @objc fileprivate func timerAction() {
        sendParam([KSocketDataType : LYSocketDataType.ping.rawValue])
    }
}

extension SocketManager: GCDAsyncSocketDelegate {
    func socket(_ sock: GCDAsyncSocket, didAcceptNewSocket newSocket: GCDAsyncSocket) {
        print("didAcceptNewSocket: \(newSocket.connectedHost ?? "")")
        DispatchQueue.main.async {
            SVProgressHUD.showSuccess(withStatus: "didAcceptNewSocket: \(newSocket.connectedHost ?? "")")
        }
        
        if isServer {
            clientSocket = newSocket
            isConnectClient = true
            newSocket.readData(withTimeout: -1, tag: 0)
        }
    }
    
    func socketDidDisconnect(_ sock: GCDAsyncSocket, withError err: Error?) {
        if let errStr = err?.localizedDescription {
            print("连接出错: \(err?.localizedDescription ?? "")")
            DispatchQueue.main.async {
                SVProgressHUD.showError(withStatus: errStr)
            }
        }
    }

    func socket(_ sock: GCDAsyncSocket, didConnectToHost host: String, port: UInt16) {
        print("成功连接服务器: \(host):\(port)")
        sock.readData(withTimeout: -1, tag: 0)
        if !isServer {
            timer.fire()
        }
    }
    
    // MARK: -  粘包拆包
    func socket(_ sock: GCDAsyncSocket, didRead data: Data, withTag tag: Int) {
        // 先存入缓存区
        dataBuffer.append(data)
        
        while true {
            guard dataBuffer.count >= bodyLegth else { break } // 保证至少有消息头, 数据大于4个字节，说明有数据

            // 获取消息头，即消息长度
            var messageLength: UInt32 = 0
            (dataBuffer as NSData).getBytes(&messageLength, length: MemoryLayout<UInt32>.size)

            guard dataBuffer.count >= Int(messageLength) + bodyLegth else { break } // 判断是否收到完整的消息

            // 获取完整的消息
            let messageData = dataBuffer.subdata(in: bodyLegth..<(Int(messageLength) + bodyLegth))

            // 处理完整的消息
            handleData(messageData, socket: sock)

            // 移除已经处理过的消息
            dataBuffer = Data(dataBuffer.subdata(in: (Int(messageLength) + bodyLegth)..<dataBuffer.count))
        }
        
        // 继续监听数据
        sock.readData(withTimeout: -1, tag: 0)
    }
    
    fileprivate func handleData(_ data: Data, socket: GCDAsyncSocket) {
        // dict : eg: {"type" : "image", "data" : "base64"}
        guard let receivedString = String(data: data, encoding: .utf8) else {
            return
        }
        
        guard let dic = jsonToDictionary(receivedString) else {
            return
        }
        
        // 事件类型
        if let type = dic[KSocketDataType] as? LYSocketDataType.RawValue {
            switch type {
            case LYSocketDataType.string.rawValue: // string类型， 如ping/pong
                guard let str = dic[KSocketDataKey] as? String else { return }
                if isServer {
                    delegate?.receivedKeyWord(str)
                }
                /*DispatchQueue.main.async {
                    SVProgressHUD.showSuccess(withStatus: self.isServer ? ("服务端收到数据: \(str)") : ("客户端收到数据 \(str)") )
                }*/
                
            case LYSocketDataType.image.rawValue:
                // base64 -> image
                let dataString = dic[KSocketDataKey] as? String
                guard let base64Str = dataString else { return }
                guard let imageData = Data(base64Encoded: base64Str) else { return }
                guard let image = UIImage(data: imageData) else { return }
                delegate?.receivedImage(image)
                
            case LYSocketDataType.touch.rawValue, LYSocketDataType.slide.rawValue: //点击事件
                handlerTouch(type: type, jsonDic: dic)
                
            case LYSocketDataType.sampleBuffer.rawValue:
                handlerSample(type: type, jsonDic: dic)
                
            default:
                print("- handleData - ")
            }
        }
    }
    
    fileprivate func handlerTouch(type: String, jsonDic: [String : Any]) {
        if isServer {
            guard let dataDic = jsonDic[KSocketDataKey] as? [String : Any] else { return }
            guard let x = dataDic["x"] as? String, let y = dataDic["y"] as? String  else { return }
            delegate?.receivedPoint(Double(x) ?? 0, Double(y) ?? 0)
            
            /*DispatchQueue.main.async {
                SVProgressHUD.showSuccess(withStatus: "client \(type) x: \(x) y:\(y) ")
            }*/
        }
    }
    
    fileprivate func handlerSample(type: String, jsonDic: [String : Any]) {
        let dataString = jsonDic[KSocketDataKey] as? String
        guard let base64Str = dataString else { return }
        guard let imageData = Data(base64Encoded: base64Str) else { return }
        delegate?.receivedSampleBuffer(imageData)

    }

    func socket(_ sock: GCDAsyncSocket, didWriteDataWithTag tag: Int) {
        //print("数据发送成功")
    }
}

解码

实现socket代理方法

func receivedSampleBuffer(_ sampleBuffer: Data) {
     self.decoder.decode(data: sampleBuffer)
}

AVSampleBufferDisplayLayer播放

private var displayLayer: AVSampleBufferDisplayLayer?
private lazy var decoder: LYH264Decoder = {
     let decoder = LYH264Decoder(width: 375, height: 852)
     decoder.returnType = .sampleBuffer
     decoder.videoDecodeSampleBufferCallback = { [weak self] (buffer) in
         guard let displayLayer = self?.displayLayer , let buffer = buffer else {
             return
          }
            
          if displayLayer.isReadyForMoreMediaData {
              displayLayer.enqueue(buffer)
          } else {
              print("播放h264失败")
          }
      }
      return decoder
}()

完结

以上代码都是demo，而且我也是刚转写Swift，需要根据自己项目改改嗷。